Question

How many molecules are contained in 90.0 g of h2o?

Answer 1

`3.01*10^24`

Explanation:

Divide 90 by the Mr of Water that is 18
`2+16=18`
then find the moles. Divide mass by the Mr.
`90/18= 5 mols`
Then multiply it by the Avogadro Constant
`5*(6.022 *10^23)`
`3.01*10^24`